1. Field of the Invention
The present invention relates to an electron emission device, and in particular, to a substrate for an electron emission device with an anode electrode and phosphor layers.
2. Description of Related Art
Generally, electron emission devices are classified into a first type where a hot cathode is used as an electron emission source, and a second type where a cold cathode is used as the electron emission source.
Second type electron emission devices include a Field Emitter Array (FEA) device, a Surface Conduction Emitter (SCE) device, a Metal-Insulator-metal (MIM) device, a Metal-Insulator-Semiconductor (MIS) device, and a Ballistic electron Surface Emitting (BSE) device.
The electron emission devices are differentiated in their specific structure depending upon the types thereof, but basically have an electron emission unit placed within a vacuum vessel to emit electrons, and an image display unit facing the electron emission unit in the vacuum vessel to emit light or to display the desired images.
With the FEA electron emission device, electrons are emitted from electron emission regions due to the electric fields formed when driving voltages are supplied to the driving electrodes placed around the electron emission regions.
However, with the electron emission device, since the distance between the substrates for forming the vacuum vessel is kept within several millimeters, and the anode electrode has a potential of several kilovolts to effect a stable luminance and lifetime effects, arcing is liable to occur due to the remnant gas within the vacuum vessel so that the image display unit can be damaged.
When the unwanted arcing occurs due to the remnant gas within the vacuum vessel, a relatively high electric current compared to the reference electric current flows through the electrode supplied with the anode voltage so that the electrode can be damaged, or the phosphor layers for the image display unit can be damaged while firing or scattering the phosphors. Consequently, the electron emission device is permanently flawed or is seriously damaged while being subjected to unrecoverable device failure.
Furthermore, with the full color electron emission device, the anode voltage is evenly supplied to the electrodes corresponding to the phosphor layers without being differentiated per the respective red, green and blue phosphor layers. In this case, the voltage application cannot properly cope with the luminance characteristics of the phosphor layers that are different from each other per the respective colors so that the luminance uniformity is deteriorated.